1. Field of the Invention
The present invention relates to an image pickup element or a mounting device therefor, for use in an image pickup apparatus such as a video camera or a digital camera.
2. Related Background Art
FIG. 1 is a vertical cross-sectional view schematically showing the configuration of an image pickup device, employing a solid-state image pickup element contained in a conventional discrete package.
In FIG. 1 there are shown a package 1 for the solid-state image pickup element; an image pickup optical lens system 2; and a position defining member 3 for defining the position of the package 1 for the solid-state image pickup element relative to the image pickup optical system 2.
The relative position of the package 1 of the solid-state image pickup element and the position defining member 3 along a plane perpendicular to the optical axis is defined by an unrepresented positioning jig. Also the relative position of the package 1 and the position defining member 3 along the optical axis is fixed by adhesion, with the impingement of the position defining member 3 on the rear face, constituting a reference plane, of the package 1. Electrode portions 4 of the package 1 pass through apertures 5 provided in the position defining member 3 and are inserted into holes 7 formed on a printed circuit board 6 positioned at the rear side of the position defining member 3, and are fixed at the rear face of the printed circuit board 6 by soldering 8 to rands formed on the rear face thereof. Also the position defining member 3, on which the solid-state image pickup package 1 is fixed, impinges on the image pickup optical system 2 for defining the position of the solid-state image pickup element 9 in the axial direction relative to the image pickup optical system 2, and positioning holes 10 provided on the position defining member 3 engage with positioning projections 11 correspondingly provided on the image pickup optical system 2 for defining the position of the solid-state image pickup element 9 relative to the image pickup optical system 2 along the plane perpendicular to the optical axis. In this configuration, a shield case 12 is mounted on the printed circuit board 6, so as to cover the electrode portions 4 of the solid-state image pickup package 1 fixed by solderings 8 to the rear face of the printed circuit board 6.
FIG. 2 is a vertical cross-sectional view, schematically showing another configuration of an image pickup device, in which the package containing the above-mentioned solid-state image pickup element is so modified that the electrode portions 4 are bent. In FIG. 2, the same portions as those in FIG. 1 are represented by the same numbers as in FIG. 1.
Referring to FIG. 2, the relative position between the solid-state image pickup package 1 and the position defining member 3 along the plane perpendicular to the optical axis is defined by an unrepresented positioning jig, while the relative position in the axial direction is fixed by adhesion, upon impingement of the position defining member 3 on the reference rear face of the solid-state image pickup package 1. The electrode portions 4 of the package 1 pass through the apertures 5 provided in the position defining member 3 and are fixed at the rear face of the printed circuit board 6, positioned at the rear side of the position defining member 3, by soldering 8 to rands formed on the front surface of the printed circuit board 6. Also the position defining member 3, on which the solid-state image pickup package 1 is fixed, impinges on the image pickup optical system 2 for defining the position of the solid-state image pickup element 9 in the axial direction relative to the image pickup optical system 2, and positioning holes 10 provided on the position defining member 3 engage with positioning projections 11 correspondingly provided on the image pickup optical system 2 for defining the position of the solid-state image pickup element 9 relative to the image pickup optical system 2 along the plane perpendicular to the optical axis.
In the conventional configuration shown in FIG. 1, however, since the electrode portions 4 are fixed by solderings 8 to the rear surface of the printed circuit board 6, such soldered portions 8 protrude on the rear side thereof and constitute a dead space against the compactization of the equipment. Also the solid-state image pickup element 9 is very susceptible to the influence of noises, but a shield case 12, if provided for avoiding such influence, increases the total thickness, hindering also the compactization of the equipment.
On the other hand, in the above-described configuration shown in FIG. 2, in which the electrode portions 4 of the package 1 containing the solid-state image pickup element 9 are bent in L-shape, the soldered portions 8 of the electrode portions 4 are present on the front surface of the printed circuit board 6 and do not protrude to the rear surface thereof, thus eliminating the dead space on the rear surface of the printed circuit board 6 as in the configuration shown in FIG. 1. Also on a surface of the printed circuit board 6, opposite to the surface electrically connected to the solid-state image pickup package 1, there is provided a ground pattern substantially covering the printed circuit board 6 to obtain the shield effect, thereby dispensing with the shield case which is a factor increasing the total thickness in the configuration shown in FIG. 2.
In the configuration shown in FIG. 2, however, in forming the electrode portions 4 into L shape, such portions have to be chucked and a chucking area for this operation has to be secured, so that the gap from the mounting face of the position defining member 3 for the solid-state image pickup package 1 to the bent position of the electrode portions 4 cannot be made small. For this reason, the distance L from the solid-state image pickup package 1 to the printed circuit board 6 has a certain lower limit, thus hindering the reduction in the total thickness. Furthermore, the length from the rear face of the solid-state image pickup package 1 to the bent position of the electrode portions 4 tends to fluctuate considerably. Also, cracking tends to appear in the forming operation if the electrode portions are chucked incompletely. Furthermore, the image pickup element may be damaged by the electromotive force generated at the forming operation.
The present invention is to resolve the drawbacks mentioned in the foregoing, and a first object thereof is to provide a surface mountable image pickup device of a thin structure for mounting.
A second object of the present invention is to provide an image pickup device and a leadless electric component mounting device, capable of reducing the total thickness of the image pickup device.
A third object of the present invention is to provide an image pickup device and a leadless electric component mounting device, capable of providing a shield effect without utilizing the shield case which is a factor for increasing the total thickness.
The above-mentioned first object can be attained, according to a preferred embodiment of the present invention, by a surface mountable leadless image pickup element in which a light receiving face is formed on the upper face in a flat package, the lower face of the package is used as a position defining face in the axial direction, and plural electrodes for soldering are formed in at least mutually opposed pair of lateral faces, among the four lateral faces, of the flat package.
Also the above-mentioned second object can be attained, according to a preferred embodiment of the present invention, by an image pickup device comprising an optical system for picking up the image of an object, photoelectric conversion means for photoelectric conversion of the object image picked up by the optical system, electric signal output means for outputting electric signals from the photoelectric conversion means, and position defining means for defining the relative position of the optical system and the photoelectric conversion means, wherein the electric signal output means is positioned between the photoelectric conversion means and the position defining means.
Also the above-mentioned third object can be attained, according to a preferred embodiment of the present invention, by a leadless electric component mounting device for mounting a leadless electric component in a mounting position in the device, comprising a position defining member for mounting the leadless electric component in a part with a predetermined gap and positioning the leadless electric component in the mounting position, and a printed circuit board electrically connected to the electrodes of the leadless electric component and derived through the above-mentioned gap.
Still other objects of the present invention, and the features thereof, will become fully apparent from the following description, which is to be taken in conjunction with the attached drawings.